The object of the present invention is a mandibular implant of ceramic material that is shaped at the bottom, where it is anchored in the mandible, like a conical helix rounded off at the end and that has a concave section to receive the epithelial sleeve and an opening to accept a denture support at the top.
Helical mandibular implants with a denture support at the top have long been known. German OS No. 2 600 639 describes an insert that is to be implaced in the jaw immediately after extraction of a tooth. The part of the insert described coverges in the shape of a cone that is rounded off at the bottom. One disadvantage of this insert is that the threading is rounded off almost to a circle and does not impede the insert working itself out. Another drawback is its single-phase design. The section to be anchored in the jaw and the actual denture support are in one piece. Thus, healing cannot proceed uninterrupted. The denture support projects out of the crest of the jaw. It constitutes an obstacle to the instinctive motion of the tongue. This displaces the implant, even though minimally, and perceptibly inhibits the healing process.
Another version is proposed in German OS No. 3 043 336. It is an implant made if necessary of a ceramic material in the shape of a conical helix with serrated threading. It has a concave section at the top to receive the epithelial sleeve and is rounded off at the bottom. A denture support can be inserted at the top, resting in a plastic mount that cushions the masticatory forces.
These known implants have one overall drawback consequent to implacement. Although, as the maxillary tissue regenerates and accumulates, it surrounds the conical section of the helix, it does not always prevent the implant from working loose and hence out of the jaw. In the implant known from OS No. 2 600 639 this is because the conical helix continues all the way up to the denture support. In that known from OS No. 3 043 336 it is because it continues up to the top, with the concave section. These implants rest accordingly in what is practically a funnel. The bone and connective tissue cannot reliably prevent an upward displacement.
Another drawback to the implant known from OS No. 3 043 336 derives from the serrated threading. The angle of the sides of the thread to the center line of the implant opens toward the bottom. This threading is intended to provide support. In spite of the cushioning of masticatory forces provided by the plastic mount, however, peaks of tension occur at the crests of the thread. These peaks severely stress the bone tissue and can loosen the implant. The serrated threading can also not prevent the implant from working out of the jaw.